Ultrafast bipolar conductivity driven by intense single-cycle terahertz pulses in a topological insulator Bi2Se3
- Ames Lab., and Iowa State Univ., Ames, IA (United States)
- Univ. of Notre Dame, IN (United States)
- Univ. of Alabama, Birmingham, AL (United States)
We present the measurement of ultrafast terahertz (THz) conductivity of a 50 nm thick topological insulator Bi2Se3 at low temperature 5 K by using a THz pump and THz probe spectroscopy scheme. Here, the THz conductivity driven by a single-cycle intense THz pump exhibits a bipolar lineshape and frequency-dependent relaxation dynamics due to the separated surface and bulk charge carriers with distinctly different scattering rates and relaxation times. We also demonstrate THz pump field-dependent excitation of the surface and bulk spectral weights, which suggests one of the optimal THz excitation conditions for generating the most charge carriers from the topology-protected surface state relative to the bulk. This also allows THz control of surface and bulk transport channels in a selective way.
- Research Organization:
- Ames Lab., Ames, IA (United States); Univ. of Alabama, Birmingham, AL (United States)
- Sponsoring Organization:
- USDOE Office of Science (SC), Basic Energy Sciences (BES). Materials Sciences & Engineering Division; USDOE Office of Science (SC), Basic Energy Sciences (BES)
- Grant/Contract Number:
- AC02-07CH11358; SC0019137
- OSTI ID:
- 1827102
- Alternate ID(s):
- OSTI ID: 1971732
- Report Number(s):
- IS-J-10,602; DEAC02- 07CH11358
- Journal Information:
- Journal of Optics, Vol. 23, Issue 10; ISSN 2040-8978
- Publisher:
- IOP PublishingCopyright Statement
- Country of Publication:
- United States
- Language:
- English
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